ISHS Acta Horticulturae 800: X International Pear Symposium
SEASONAL DYNAMICS OF SECONDARY METABOLITES IN LEAVES OF 'CONFERENCE' PEAR |
| Authors: | M. Colaric, F. Stampar, M. Hudina |
| Keywords: | pear, Pyrus communis, leaves, growing season, phenolic compound, HPLC |
| Abstract:
The phenolic variation in pear leaves of the cultivar 'Conference' was investigated monthly during the growing season 2004 from May to October. Chlorogenic, sinapic, vanillic, syringic and caffeic acid, as well as rutin, catechin and epicatechin were determined with the High Performance Liquid Chromatography (HPLC). Chlorogenic acid was the major identified phenolic, followed in contents by rutin, syringic acid, epicatechin, catechin, vanillic, caffeic and sinapic acid. Only in the first sampling date did rutin predominate among the analysed compounds, and then in the next sampling dates the content of chlorogenic acid was always the highest. The results showed significant differences in the contents of individual phenolics between sampling dates. Generally, the seasonal dynamic of individual phenolics was rather similar: the lowest values of analysed phenolics were observed at the first sampling date (May), then their contents increased, reaching a peak at the third sampling date (July) and after that their contents decreased slowly. Exceptions were syringic acid and epicatechin, of which the contents increased until the fifth sampling date (September), but after that their contents also decreased; similarly to the dynamic of the other phenolics. The biggest increase, from the lowest to highest content, was achieved with syringic acid, which increased up to 80.2-fold, then chlorogenic acid up to 33.0-fold, epicatechin up to 14.3-fold, caffeic acid up to 9.0-fold, catechin up to7.8-fold, and after that rutin only up to 3.7-fold, sinapic acid up to 3.2-fold and vanillic acid up to 2.8-fold. The phenolic dynamic in 'Conference' leaves during growing season was shown. Generally, this dynamic was quite similar to that reported previously for 'Williams' leaves, but the contents of some phenolics were higher in the previous study. | |
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